/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.io;

import java.io.*;

/**
 * This DataEntryWriter delegates to one of two other DataEntryWriter instances, depending on whether the data entry
 * passes through a given data entry filter or not.
 *
 * @author Eric Lafortune
 */
public class FilteredDataEntryWriter implements DataEntryWriter {
    private final DataEntryFilter dataEntryFilter;
    private DataEntryWriter acceptedDataEntryWriter;
    private DataEntryWriter rejectedDataEntryWriter;

    /**
     * Creates a new FilteredDataEntryWriter with only a writer for accepted data entries.
     * 
     * @param dataEntryFilter the data entry filter.
     * @param acceptedDataEntryWriter the DataEntryWriter to which the writing will be delegated if the filter accepts
     *        the data entry. May be <code>null</code>.
     */
    public FilteredDataEntryWriter(DataEntryFilter dataEntryFilter, DataEntryWriter acceptedDataEntryWriter) {
        this(dataEntryFilter, acceptedDataEntryWriter, null);
    }

    /**
     * Creates a new FilteredDataEntryWriter.
     * 
     * @param dataEntryFilter the data entry filter.
     * @param acceptedDataEntryWriter the DataEntryWriter to which the writing will be delegated if the filter accepts
     *        the data entry. May be <code>null</code>.
     * @param rejectedDataEntryWriter the DataEntryWriter to which the writing will be delegated if the filter does not
     *        accept the data entry. May be <code>null</code>.
     */
    public FilteredDataEntryWriter(DataEntryFilter dataEntryFilter, DataEntryWriter acceptedDataEntryWriter,
        DataEntryWriter rejectedDataEntryWriter) {
        this.dataEntryFilter = dataEntryFilter;
        this.acceptedDataEntryWriter = acceptedDataEntryWriter;
        this.rejectedDataEntryWriter = rejectedDataEntryWriter;
    }

    // Implementations for DataEntryWriter.

    public boolean createDirectory(DataEntry dataEntry) throws IOException {
        // Get the right data entry writer.
        DataEntryWriter dataEntryWriter =
            dataEntryFilter.accepts(dataEntry) ? acceptedDataEntryWriter : rejectedDataEntryWriter;

        // Delegate to it, if it's not null.
        return dataEntryWriter != null && dataEntryWriter.createDirectory(dataEntry);
    }

    public boolean sameOutputStream(DataEntry dataEntry1, DataEntry dataEntry2) throws IOException {
        boolean accepts1 = dataEntryFilter.accepts(dataEntry1);
        boolean accepts2 = dataEntryFilter.accepts(dataEntry2);
        return accepts1
            ? !accepts2 || acceptedDataEntryWriter == null
                || acceptedDataEntryWriter.sameOutputStream(dataEntry1, dataEntry2)
            : accepts2 || rejectedDataEntryWriter == null
                || rejectedDataEntryWriter.sameOutputStream(dataEntry1, dataEntry2);
    }

    public OutputStream createOutputStream(DataEntry dataEntry) throws IOException {
        // Get the right data entry writer.
        DataEntryWriter dataEntryWriter =
            dataEntryFilter.accepts(dataEntry) ? acceptedDataEntryWriter : rejectedDataEntryWriter;

        // Delegate to it, if it's not null.
        return dataEntryWriter != null ? dataEntryWriter.createOutputStream(dataEntry) : null;
    }

    public void close() throws IOException {
        if (acceptedDataEntryWriter != null) {
            acceptedDataEntryWriter.close();
            acceptedDataEntryWriter = null;
        }

        if (rejectedDataEntryWriter != null) {
            rejectedDataEntryWriter.close();
            rejectedDataEntryWriter = null;
        }
    }

    public void println(PrintWriter pw, String prefix) {
        pw.println(prefix + "FilteredDataEntryWriter (filter = " + dataEntryFilter + ")");
        if (acceptedDataEntryWriter != null) {
            acceptedDataEntryWriter.println(pw, prefix + "  ");
        }
        if (rejectedDataEntryWriter != null) {
            rejectedDataEntryWriter.println(pw, prefix + "  ");
        }
    }
}
